Light travel at different speeds in different medium

In summary, the conversation revolves around the question of why light travels at different speeds in different mediums and why this speed is dependent on frequency, as seen in dispersion. The individual asking the question is not looking for an explanation based on Snell's law or Hugens's Principle, but rather a more fundamental explanation related to the properties of different mediums. They are directed to a relevant FAQ thread on photon transport in a medium for further information.
  • #1
hbal9604@usyd
6
0
hey, I was just wondering if someone could give me an explanation about the following:

1. why, physically, does light travel at different speeds in different medium

2. why is the speed at which it travels through different media dependent of frequency, as is the case with dispersion.

please don't explain snell's law. I know the equations. But the index of refraction is just a piece of algebraic information all bundled up in a package that you substitute in.

I'm also aware of Hugens's Principle which explains how refraction works due to the changed velocity due to the medium in question.

What I'm after is a more fundamental explanation, eg, relating to the inherent properties of glass vs water etc,

Thanks a lot!
 
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  • #2


You may want to start by reading an entry in the FAQ thread in the General Physics forum. The discussion on photon transport in a medium might be relevant.

Zz.
 

FAQ: Light travel at different speeds in different medium

Why does light travel at different speeds in different mediums?

Light travels at different speeds in different mediums because it interacts with the atoms and molecules in the medium. The speed of light is determined by the medium's refractive index, which is a measure of how much the material slows down the speed of light passing through it.

How does the refractive index of a medium affect the speed of light?

The refractive index of a medium is directly proportional to the speed of light in that medium. This means that the higher the refractive index, the slower the speed of light will be in that medium.

Why does light travel faster in vacuum compared to other mediums?

In a vacuum, there are no atoms or molecules for light to interact with, so it can travel at its maximum speed of 299,792,458 meters per second. In other mediums, the interaction with atoms and molecules slows down the speed of light.

Does the wavelength of light change when it travels through different mediums?

Yes, the wavelength of light changes when it travels through different mediums. This is because the speed of light changes, and according to the equation c = fλ, if the speed changes, the wavelength must also change to maintain a constant frequency.

How does light behave when it travels from one medium to another?

When light travels from one medium to another, it can either be reflected, refracted, or absorbed. This depends on the angle at which the light hits the new medium and the difference in refractive indices between the two mediums. The change in speed and direction of light as it passes through different mediums is known as refraction.

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